In this paper, the active buckling control of Smart functionally graded (FG) plates using piezoelectric sensor/actuator patches is studied. A simply supported FG rectangular plate which is bonded with piezoelectric rectangular patches on the top and/or the bottom surface(s) as actuators/sensors is considered. When a constant electric charge is imposed, the governing differential equations of motion are derived using the classical laminated plate theory (CLPT). The solution for the equation of motion is obtained using a Fourier series method and the effect of feedback gain on the critical buckling load for PZT-4 is studied .The buckling behavior of Smart plate subjected to compressive load is also investigated. The sensor output is used to determine the input to the actuator using the feedback control algorithm. The forces induced by the piezoelectric actuators under the applied voltage field, enhance the critical buckling load.

In this research, a control feedback system is used to study the free vibration response of rectangular plate made of magnetostrictive material (MsM) for the first time. A new trigonometric higher order shear deformation plate theory are utilized and the results of them are compared with two theories in order to clarify their accuracy and errors. Pasternak foundation is selected to modelling of elastic medium due to considering both normal and shears modulus. Also in-plane forces are uniformly applied on magnetostrictive nano-plate (MsNP) in x and y directions. Nonlocal motion equations are derived using Hamilton’s principle and solved by differential quadrature method (DQM) considering different boundary conditions. Results indicate the effect of various parameters such as aspect ratio, thickness ratio, elastic medium, compression and tension loads and small scale effect on vibration behaviour of MsNP especially the controller effect of velocity feedback gain to minimizing the frequency. These finding can be used to active noise and vibration cancellation systems in micro and nano Smart structures.

An effective wide-band, active control law based on a type of Dynamic Vibration Absorber (DVA) was proposed and investigated in this study. Using the mechanical impedance method, an active DVA control law was formulated based on the passive mechanical model. The resulting electrical DVA was capable of generating multi-mode active damping to its attentive structure. The host structure was an aluminum plate with an acceleration signal fed back through the controller to a collocated piezoelectric actuator. An experimental system was constructed employing the DVA and an open loop analysis showed that the control system had better a roll-off property than the Direct Velocity Feedback (DVF) controller. Furthermore, real time control results demonstrated that the multiple vibration modes can be simultaneously suppressed. In addition, the measured sound isolation performance below 1 kHz was found to be as high as 6 dB. The proposed method is simple and effective and is readily applicable to a variety of structures.

Magneto-electro-elastic materials are multiphase Smart materials that exhibit coupling among electrical, magnetic and mechanical energy fields. Due to this ability, they have been the topic of numerous research in the past decade. In this paper, buckling behavior of a multiphase magneto-electro-elastic rectangular plate with simply supported boundary conditions is investigated, based on Reddy’ s higher-order shear deformation theory. Gauss’ s laws for electrostatics and magnetostatics are used to model the electric and magnetic behaviors of the plate. The partial differential equations of motion are reduced to ordinary differential equations by using the Galerkin method. Then, the closed-form expression for the critical buckling load of the plate considered is obtained. Some examples are presented to validate the study and to investigate the effects of some parameters on the critical buckling loads of the multiphase magneto-electroelastic rectangular plates. It is found that the buckling behavior of the magneto-electro-elastic plate is dominated by the elastic properties of the plate, and magneto-electric coefficients slightly increase the critical buckling load of the plate.

Structural health monitoring (SHM) systems operate online and test different materials using ultrasonic guided waves and piezoelectric Smart materials. These systems are permanently installed on the structures and display information on the monitor screen. The user informs the engineers of the existing damage after observing the signal loss which appears after damage is caused. In this paper, monitoring is done for plate shaped structures made of ST-37 steel. After conducting the experimental tests, the stored signals by the multi-layer artificial neural network algorithm are processed and the damage caused in the plate is detected. By analyzing the graphs, it becomes clear that after causing damage the signal amplitude decreases. In the experimental test, two piezoelectric discs are used on a steel plate which has been installed using a strong adhesive. Using a strong adhesive improves wave propagation in the structure. Developing innovative testing methods for the SHM system has caused better control in structures after assembly.